This study describes qualitatively a psychoeducational assertiveness intervention for 20 women's perceptions of positive and negative experiences, undertaken to identify whether therapeutic mechanisms operating in group therapy as described by Yalom might be inferred. There were 14 90-min. weekly sessions organized around educational material. Two groups were conducted with 10 university women each (M= 20.9 yr., SD= 1.9). Qualitative analysis of the 20 interviews identified five of Yalom's therapeutic mechanisms, namely, self-understanding, universality, acceptance, catharsis, and self-disclosure. The positive experiences were group cohesiveness, self-understanding, self-disclosure, positive views about the self and learning, and cognitive benefits. Self-disclosing at the early stages of group development was the most frequently reported negative experience or difficulty in the group. Although participants stated they improved interpersonal communication skills, analysis suggested the cultural context was an important mediator of assertive behavior.